[depthcharge623]

I am brand new to brewing... just bottled my first beer-- an Oktoberfest from an extract kit.

I have been doing research to wrap my mind around the concepts of brewing, and do not entirely understand how fermentable sugars affect the beer besides ABV.  I know that a non-fermentable sugar, like maltodextrin, will not affect ABV, but only affect the density of the beer.  Other non-fermentables would affect either the density/mouthfeel or flavor.

But I'm wondering how much effect a fermentable has on the flavor or mouthfeel?  Like will some product that is supposed to be 100% fermentable have an influence over the flavor or mouthfeel?

[morticaixavier]

flavor compounds are not particularly related to sugars perse.

However most sugar sources have some flavor compounds as well. if those compounds are plentiful enough, and not so volatile as to be completely blown off by an active fermentation then they will affect the flavor of th finished beer.

additionally, alcohol both has a flavor of it's own, and will enhance and transport flavor molecules from other sources. In this way the amount of fermentables will affect the character of the finished beverage.

mead is a good example, honey is more or less completely fermentable assuming you don't add too much for the yeast to handle. what's left behind are alcohol, flavor and aroma molecules that were heavy enough and stable enough to survive the heavy scrubbing from co2 during fermentation, and of course yeast byproducts. What you are left with is essentially the flavor of honey which is separate from the sweetness of honey. It often smells and tastes something like the flowers it was collected from.

with beer it's more complicated because there are a lot of processes going on before you ever touch the ingredients and each of these has an effect on the flavor molecules present in the grain, hops, sugar, etc. but the basic concept is the same, the fermentable sugars will be turned into alcohol and co2. the yeast will produce and excrete not only alcohol and co2 but also a variety of esters, phenols, and other substances that will have flavor and aroma. but the hops, the grain, and whatever adjuncts you might have added will have their own flavor substances that will either remain, be blown off by the fermentation, or be transformed by the yeast into something else.

[depthcharge623]

flavor compounds are not particularly related to sugars perse.

However most sugar sources have some flavor compounds as well. if those compounds are plentiful enough, and not so volatile as to be completely blown off by an active fermentation then they will affect the flavor of th finished beer.

additionally, alcohol both has a flavor of it's own, and will enhance and transport flavor molecules from other sources. In this way the amount of fermentables will affect the character of the finished beverage.

mead is a good example, honey is more or less completely fermentable assuming you don't add too much for the yeast to handle. what's left behind are alcohol, flavor and aroma molecules that were heavy enough and stable enough to survive the heavy scrubbing from co2 during fermentation, and of course yeast byproducts. What you are left with is essentially the flavor of honey which is separate from the sweetness of honey. It often smells and tastes something like the flowers it was collected from.

with beer it's more complicated because there are a lot of processes going on before you ever touch the ingredients and each of these has an effect on the flavor molecules present in the grain, hops, sugar, etc. but the basic concept is the same, the fermentable sugars will be turned into alcohol and co2. the yeast will produce and excrete not only alcohol and co2 but also a variety of esters, phenols, and other substances that will have flavor and aroma. but the hops, the grain, and whatever adjuncts you might have added will have their own flavor substances that will either remain, be blown off by the fermentation, or be transformed by the yeast into something else.

Thanks, that helps a lot!  I guess I was thinking about "completely fermentable" in slightly different terms.  More or less, if the yeast ferments 100% of the mass going in, I would consider that complete.  So if we fermented a mixture of pure glucose and water, the result would be water, ethanol, and CO2, since there were no esters or flavor compounds to be left over.  But I guess your example of honey is 100% fermentable in the sense that all the sugar in honey will be fermented.  But there are other compounds in honey that are not sugar that would not be fermented, and would affect the flavor or nose of a beer.

So I guess you've almost got 3 different classes:

1) "Sugars" which are either 100% monosaccharides , or polysaccharides that yeast can completely break down into monosaccharides and ferment. Example would be something like pure cane sugar (sucrose).

2) "Sugars" which contain monosaccharides/fermentable polysaccharides that are completely fermentable, and other non-sugars which affect scent, flavor, and texture.  Example would be honey or maybe molasses?

3) A non-fermentable sugar which remains in the beer as it went in.  This affects texture, density, or flavor.  An example would be maltodextrin.

Do I have that about right?

[morticaixavier]

more or less right. however on the esters front, those are generated by the yeast during fermenation. so even with a 100% fermentable flavor neutral feedstock you can still get some esters, phenols, and other yeast derived compounds that will affect flavor and aroma.

[santoch]

I'll second that and expand on the concept of yeast flavor/aroma contributions.

It was a huge eye opener for me the first time I split a wort and used 2 different yeasts then compared the results side by side.  They seemed like they could NEVER have been from the same boil.

Most newbies totally underestimate the contributions that yeast make to the flavor and aroma of a beer.  So much so, that other than the obvious roast/caramel/bread/toast that you get from the various specialty malts, the yeast is what really defines the flavor profile of the beer. 

[ynotbrusum]

I'll second that and expand on the concept of yeast flavor/aroma contributions.

It was a huge eye opener for me the first time I split a wort and used 2 different yeasts then compared the results side by side.  They seemed like they could NEVER have been from the same boil.

Most newbies totally underestimate the contributions that yeast make to the flavor and aroma of a beer.  So much so, that other than the obvious roast/caramel/bread/toast that you get from the various specialty malts, the yeast is what really defines the flavor profile of the beer. 

+1 - yeast do most of the heavy lifting on flavor/no off flavors with most beers.

[erockrph]

I'll second that and expand on the concept of yeast flavor/aroma contributions.

It was a huge eye opener for me the first time I split a wort and used 2 different yeasts then compared the results side by side.  They seemed like they could NEVER have been from the same boil.

Most newbies totally underestimate the contributions that yeast make to the flavor and aroma of a beer.  So much so, that other than the obvious roast/caramel/bread/toast that you get from the various specialty malts, the yeast is what really defines the flavor profile of the beer.

+2 - The best way I like to describe this is lagers. Even though the hallmark of a lager is a clean fermentation with minimal byproducts, lager yeasts still leave a fingerprint. You can still tell that a beer is a lager by the taste of it. And there are a wide assortment of lager yeasts. If the yeast didn't affect flavor, you'd only need one or two.

More than anything else, yeast is what defines the "house flavor" for most breweries. Even cleanly fermented beers with a clean yeast strain leave behind a fingerprint.

[majorvices]

to add to all this, the way you handle your yeast will add much to your beer flavor. Yeast can provide as much as 80% of the beer's flavor, and if you don't pitch enough yeast, don't control the temperatures and don't give the yeast the correct amount of aeration at the beginning of fermentation 80% of that flavor can be unwanted off flavors.

[depthcharge623]

That all makes sense.

So let's say I do a batch with only grain, no hops or other adjuncts. Would the type of grain be negligible in terms of flavor compared to the yeast?

[denny]

That all makes sense.

So let's say I do a batch with only grain, no hops or other adjuncts. Would the type of grain be negligible in terms of flavor compared to the yeast?

Nope, not at all.  They'd both play parts.  Which one would play a bigger role would depend on the type of grain and yeast used.  BTW, don't make a beer without hops! 

[depthcharge623]

That all makes sense.

So let's say I do a batch with only grain, no hops or other adjuncts. Would the type of grain be negligible in terms of flavor compared to the yeast?

Nope, not at all.  They'd both play parts.  Which one would play a bigger role would depend on the type of grain and yeast used.  BTW, don't make a beer without hops! 

I wouldn't make a beer without hops, I'm just trying to limit my variables for this conversation so I can comprehend better.

[denny]

That all makes sense.

So let's say I do a batch with only grain, no hops or other adjuncts. Would the type of grain be negligible in terms of flavor compared to the yeast?

Nope, not at all.  They'd both play parts.  Which one would play a bigger role would depend on the type of grain and yeast used.  BTW, don't make a beer without hops! 

I wouldn't make a beer without hops, I'm just trying to limit my variables for this conversation so I can comprehend better.

Yeah, I figured that, but ya never know....

[klickitat jim]

Fermentables would be anything fermentable, right? Malt is a fermentable and everything else is an adjunct. A lot of folks would say the adjunct list includes corn, rice, and different sugars. Thats true until you get into bugs. Some things can eat more than just sugar. Brett can process the cellulose in oak, for example.

Oh, and you sure can make beer without hops. But you'll need to get your bite from somewhere else, like lacto maybe.

[morticaixavier]

I make a beer without hops about once a year. I use heather tips instead. lovely.

Jim,

fermentables are anything fermentable. malted barley is separated from adjuncts (anything that is fermentable but NOT malted barley)

[klickitat jim]

Cool! So, the term fermentable depends on what is being pitched. Some things are unfermentable to sac yeast but fermentable to brett. Or so I'm told. Its not like I've watched them do it personally.